Automatic brake mechanism



H. F. GERHART. AUTOMATIC BRAKE MEcHAmsM.

APPLICATION FILED OCT. I9, 1920.

Patented May 23, 1922.

2 SHEETS-SHEET I.

l www# H. F. GERHART. AUTOMATIC BRAKE MECHANISM.

APPLICATION FILED OCT. 19. 1920.

Patented May 23, 1922.

2 SHEETS-SHEET 2.

lia Si HARVEY F. GERHABT, 0F FELADELPHA, PENNSYLVANIA.

AUTOMATIC BRAKE MECHANISM.

reiten.

Specification of Letters Patent. Pgpbqgntgd Mfgmr 233 1922 Applicationfiled. Detener 19, 1920. Serial No. 413,960.

To all' `w/wml t may conce/M1,

Be it known that l, l-lAnvn'r F. Gnnrinnr, a citizen of the UnitedStates` residing at Philadelphia, in the county of Philadelphia andState of Pennsylvania, have invented certain new and useful Improvementsin Automatic Brake Mechanisim of which the following` is a specication,reference being had to the accompanying drawings.

On street cars the brakesare usually. ap-v plied by` hand-power through`the mediumA of a hand wheel mounted uponll the upper end of the brakestem or shaft, and in using this form of means for applying the brakes,

considerable pressure and strength are necof the present invention is toeliminate .the use of hand-power in applying brakes, and inview thereofprovision of means between the 4drive axle and the brake stem isafforded, so as to utilize the power from the drive axle to apply thebrakes. l A .further purpose is the provisions. of driving Aconnectionsbetween the drive aXle and the brake stem including means to be moved'rinto and out of gear with the drive axle, sothat the brake shoes can beapplied automatically.whenever it is desired:

Another purpose is the provision of means to apply the `brakes when thecar is moving forwardly or rearwardly.

A further purpose embodies the provision of slidable connections betweenthe brake stem and the drive axle of the truck, so that when the truckof the car turns when the car is going around a curve, the connectionsbetween the brake stem and the drive axle may shorten or lengthen. y

A still further purpose consists in the provision of means to permit thebrake stern to be rotated and its connections with the brake mechanism(not shown) to be wound on the stem, without turning the hand wheel atthe upper end thereof, in combination with means to hold the hand wheelto prevent retrograde movement of" the hand wheel after the brakes havebeen applied, said last mentioned means being releasable, in order torelease the hand tical form for commercial purposes, the' invention maybe susceptible of changes, and the right to these changes is claimed.provided they are comprehended within the `scope of what is claimed.

The linvention comprises further features and combination of parte, aswill be hereinafter set forth, shown in the drawings and` claimed.

. Figure -1 is a longitudinalsectional View cfa conventionalconstruction of street car, showing the application of the preferredembodiment of the invention.

Figure 2 is a sectional View on line 2 2 of Figure 1.

`Figure 3Vis a sectional view on line 3-3 of Figure 1. p l

Figure is a plan view of the brake stem and the handwheel, showing themeans to permit the brake stem to rota-te and wind upon the brake chainwithout turning the vhand wheel. Y

Figure 5 is a detail sectional view on line 5 5 of Figure 4.

. Figure y(iis a detail sectional View on line 66vof Figure 4.

Figure is a'detail sectional view on line 7-7 of Figure- 1.

Figure-.8 is a longitudinal sectional view through a portion of theStreetcar showing the application of a modified embodiment of theinvention.

Referring to the drawings, 1 designates a portion of conventional formof street car, and mounted in suitable bea-rings, such as indicated at 2isa brake stem 3, the upper portion of which is-mounted in a bearing 4of a bracket 5, which is attached in any suitable manner to the dash 6of the car. Engaged with4 the upper end of the stein 3 and resting oncolla-r or shoulder 7 is the ub of a conventional form of hand wheel 9.-he hub 8 is hollow, and located therein and `secured by apin 10 on thestem is a ratchet wheel-1li. cap 12 is engaged with the upper extremityof the stem, there being anut 13 secured on the stem to hold the cap inplace. The cap telescopes over the hollow hub of the hand wheel, andnecessarily prevents collection of foreign matter in the hub.` The hub 8has an off-set portion 14 provided with a cavity 15, and pivotallymounted therein is a spring tensioned pawl 16, which engages the teethof the ratchet 11. Carried byy the spokes of the hand wheel is a ratchetring 17, and pivotally mounted at L8 on a support 19 is a hand pawl 20.This hand pawl is also spring tensioned, so as to hold its tooth 21 inengagement with the teeth of the ratchet ring. It will be noted thatwhen the brake stem 3 is rotated in the direction of the arrow a,through power transmitted thereto from the drive axle, the stem is freeto rotate, without carrying the hand wheel 9 with it. When the power isrelieved on the stem and the brake mechanism applied, there'is tensionon the stem, through the medium of the brake connections, hence thespring tensioned pawl in the cavity 15`will engage the teeth of theratchet 1l andpreventfietrograde movement of the stem, since the handwheel is prevented from retrograde movement by the tooth 21 ofthe'pa'w'l 20.

The form of street car herein shown is more or less'illustrative and ofa conventional construction for the purpose ofshowing'an application ofthe brake actuating mechanism.

However itis well known lthat'the trucks of a street car which carry thesupporting wheels are permitted to have slight pivotal movements, henceit is necessary in con# structing the present actuating mechanism, toprovide a looseness of play between the pafts connecting the stem andthedrive ax e.

Mounted on the truck 22 of the car is a drive axle 23, on which asupportingwheel 24 is mounted. It is obvious that'the axle 23 isdesigned to carry a pair of supporting wheels, but only one wheel isillustrated. Also carried by the axle 23 is a bevel gear 25. A verticalshaft 26 is mounted in a bearing of the truck 22 and in a bearing 27,which is carried by the axle 23, and rotatable with the shaft 26 is adouble bevel gear, the lower teeth 29 of which engage theteeth ofthebevel gear 25, while the upper teeth 30 engage the teeth of ay bevelgear 31, which is mounted upon the shaft section 32. vOne end of thisshaft section 32 is mounted in a bearing of a yoke 33, which straddlesthe vertical shaft 26, there being a bolt 34 engaging through the armsof the yoke to hold the stem in positionon the shaftV 26.v vThe shaftsection 32 is mounted in abearing 35 of an arm of thetruck 22. Theshaft'section y32 comprises two parts 36`and37fwhich aref'united bymeans of a universal joint 38. The part 37 of the shaft section 32 ispreferably rectangular in cross section, and'telescopically fits acorrespondingly shaped bore 39 of the shaft section 40.

y TheJ forward end of the shaft section 40 is rotatable in a strapbearing 41, there being vshoulders 42 to prevent axial movement of theshaft section 40 relatively 'to the strap i' bearing." The strap bearing41 hasaring portion 4 3, and pivotally cnnectedat 44 to theringportionfis a link 45,"'whi'ch""in turn is pivotally connected to anarm 46 which is carried by a shaft 47 which is mounted in bearings 48 ofthe car, and on one end of the shaft a lever 49 is mounted for operatingthe same. The usual brake bar 50 (which is designed for connection withthe brake mechanism not shown) is provided, and connected to the forwardend thereof is a brake chain 5l, which in turn is connected to andpartly wound about the brake stem 3. kIt is obvious that when the brakestem 3 is rotated in thedirection of the arrow a, the chain 51 will bewound upon the stem, and the brake shoes of the brake mechanism applied.f

Fixed on the lower end of the brake stem 3 are bevel gears 52 and 53. Ayoke 54 straddles the lowerl end of the stem between'the gears 52 and53, there being a bolt 55 Vengaging'through the arms of the yoke to holdit in place. The forward reduced end 56r of the shaft section 40 ismounted in the yoke 54, there beingva head 57 secured by a' pin 58 onthe reduced end. to hold the parts connected. The shaft section 40'has abevel gear 59 on its end designed to mesh with either one of the bevelgears 52 and 53. i

Inorderto appl the brake shoes of the brake mechanism" Znot shown), themotorman may grasp the lever 49 and move the same rearwardly, which willimpart a downward movement of the connections with the shaft 40, andtilt the shaft so ythat the bevel gear 59 will mesh with the gear 52.Aboveand below the yoke 54 springs 53a and 52*L are arranged, acting tohold the yoke centered between the bevel gears 52 and 53, and the bevelgear 59 out of engagement with the gears 52 and 53. However when thegear 59 is moved downwardly in mesh with the gearv52 the spring 52l iscompressed, and when the gear 59 is moved up in mesh with the gear 53,thc spring 53a is compressed. When hand power is released on the lever49, the gear 59 automatically becomes disengaged from one or the otherof the gears 52 and'53. lVhen the gear 59 is moved in mesh with the gear52` the axle 23 will transmit `power to the shaft 2'6 through the gear29, and then through the shaftsection 40, and since the shaft 32is'slidably connected with the shaft section 40 power may be transmittedto the brake stem 3. which will cause the brake" chain to wind thereon.As the chain 4l winds on the stern, pulling action will be imparted onthe brake bar 50, thereby cans` ing the brake shoes of the brakerriecha` nism to be applied. A movement of the lever 49 in a forwarddirection, will move the gear 59 in mesh with the bevel gear' 53,which'will causefthe brake shoesv of the brake mechanism to beappliechwhen the car is moving rearwardly. A Y

The telescopical connections between the shaft section 32 and the shaftsection d() are afforded, so as to accommodate the slight pivotalmovements of the trucle which carry the drive a'xleand supportingwheels. Also the universal joint 38 isprovided in order to permit of theslight pivotal connection of the truck relatively to the shaftconnections between the drive axle and the brake stemA lVhen the brakestem 3 is rotated. and the chain 5l winds thereon, it rotates withoutturning or rotating the hand wheel 9. soon as the levere?) is released`and the bevel gear 59 is disengaged from 52, the

brake chain 5 1 acts to reverse the movement ofthe stem 3. However thisis prevented by means of the spring tensioned pawl, while the hand wheelis prevented from retrograde movement by the hand wheel pawl 20. When itis desired to release the brake mechanism, the hand pawl is depressed,disengaging the tooth 21 from the teeth of the ratchet ring 17, then themotori man may permit the hand wheel to rotate or move through thehands, allowing the brake shoes to return to their normal positions.

In Figure 8 the driving connections between the stem 3 and the driveaxle are somewhat reversed. For instance instead of the shaft section 40being tilted at its forward end, the shaft section 32 is tilted at itsrear ends, in order to apply the brake mechanism. Mounted upon the shaft26 in Figure 8 is a double gear, the lower teeth 62 of which engage theteeth of the gear 25, while the upper teeth 63 are utilized intransmitting power to theshaft section 32. Also on the shaft 26 is abevel gear 64 oppositely disposed to the teeth 63 of the bevel gear 6l..As previously stated the rear end of the shaft section 32 is raised orlowered, for the purpose of causing its bevel gear 65 to mesh eitherwith the teeth 63 of the bevel gear 61 or with the bevel gear 614-. Alink 66 is swivelled between the shoulders 67 of the shaft section 32,and is in turn pivoteil to one arm of the bell crank lever 68, which ispivotally mounted at 69 on the truclr of the car. The other arm of thebell crank lever is connected to the lever 49 by means of the linlr 7 O.It is obvious that by moving the lever 49 in Figure 8 rearwardly, thelink 70 will move forwardly, and the bell crank lever 68 tilteddownwardly, thereby cans ing the bevel gear 65 to mesh with 63, hencethe brake stem 3 will be rotated in the direction of the arrow t inFigure 8, causingthe brake shoes of the brake mechanism to be applied. Areverse movement of the lever 49 in Figure 8 will raise the gear 65 intomesh with'the gear 64, causing the brake shoes of the brake mechanism tobe applied when the car is moving rearwardly.

The shaft section 40 in Figure 8 is mounted in a strap bearing` 7l,which is swivelled between the shoulders 72. This strap bearing has aring portion 73, and the upper portion of the strap bearing` is'seciuedat 7lto the underfare oi' the floor of the car. rlihe brake chain 51 iuthe i'ncforred and modified embodiments of the invention more throughthe ring portions l-i and 7? of thc strap bearings. The shaft section 82in Figure 8 is mounted in a slot 75 of the arm T6 of the yoke. This slotentends vertically. so as to permit a raising and lowering; of the shaftsection 22. However the slot is of a width, to prevent lateral movementof the shaft section 32 in Figure 6.

The yoke 33 is similar in construction `to the yoke 54.

In Figure 8 the lever 459 may be held in different adjusted positions bymeans of the hand grip operated dog 60 engaging the rack.

The invention havingr been set forth, what is claimed. as being usefulis l. In a mechanism for automatically applyinej brakes, the combinationwith a brake stem having means for connection with brake shoes, of adriving mechanism for the stem, means shiftably connecting the mechanismand the stem for periodically transmitting power to the stem, means forshifting said shiftable means, whereby the stem may be periodicallyoperated, a hand wheel loosely mounted on one end of the stem, a ratchetand pawl device connecting the hand wheel and the stem to hold the wheelmovable with the stem in one direction, said hand wheel having a bandratchet, a fixed support, and a pawl mounted on the support and engagingthe band ratchet, to hold the hand wheel against movement in theopposite direction, while-the stem is being driven by the drivingmechanism to apply the brakes.

2. In a mechanism for automatically ap'- plying brakes, the combinationwith periodically driven and continually driving elements, of anextensible and flexible counector, one end of said connector beingshiftably connected in and out of gear with one of said elements, theother end of said connector being positively operatively connected tothe other element., m ans manually operated and operatively connectedwith the connector for shifting it into gear with one of said elements,for driving the same means operatively connected with one of theelements, and in turn adapted to counect with the brake shoes, wherebyupon driving said element the brake shoes may be applied, a hand wheelon one end of one of the elements, a ratchet and pawl connecting thehand wheel and its element to permit its element to rotate in onedirection, a band ratchet, a fixed support, and a manually operateddevice to engage the band ratchet to hold the hand wheel against movement, whereby the element on which the hand wheel. is mounted may rotateindependently of the hand wheehibr applying the brake shoes.

3. In a mechanism for automatically applying brakes, a brake stem havingmeans for connection with the brake shoes, a drivingy mechanism, anextensible and flexible shaft operatively connected to and driven bysaid driving mechanism, a pair of opposed driven members on said stem7means carried by said shaft and adapted to engage with one or the otherof said opposed driven members, a yoke straddling said stem and beingConnected vto the end of said shaft for guiding the shaft in itsshifting` movement, yieldable means between the yoke and each of thedriven members, for holding the member Carried by the shaft in a neutralposi tion between the opposed driven members, means manually aetuatedfor 'shifting the shaft into and out of gear with one or the other ofsaid driven members of the stem, means for holding andpreventingretrograde movement of the stem whenit is driven to apply thebrake shoes, and means to permit of the release of said stem when theshaft is shifted to a neutral position7 whereby the brake shoes mayreturn to normal positions.

In testimony whereof I hereunto aix my signature. y

HARVEY F. GERHART.

